The units, developed by researchers at the American Institute of Physics, use water to overcome an issue faced by other suction-based robots and novel climbing devices.
Researchers Xin Li and Kaige Shi said previous vacuum suction devices could not maintain suction on rough surfaces due to leakage, which leads to suction failure – and the potential for a heavy robot to fall from height.
To build suction units that work on “rough surfaces, no matter how textured” the colleagues developed a ‘zero-pressure difference’ (ZPD) method. Their technique overcame leakage by using a high-speed rotating water ring between the surface and suction cup to maintain the vacuum.
The centrifugal force of the rotating water apparently eliminates the pressure difference at the boundary of the vacuum zone to prevent vacuum leakage, maintaining high vacuum pressure inside the suction cup.
The suction unit is reportedly energy-efficient, and smaller and lighter than conventional designs. The researchers tested their unit with three different suction sizes and applications – on a robotic arm to grip and handle objects, on a hexapod wall-climbing robot and on a Spider-Man-style wall-climbing device.
“There are many applications of our design, but we think the wall-climbing robot will be the most useful,” said Li. “Compared to other wall-climbing robots, the robot with our ZPD-based suction unit achieves surprising improvement in performance.”
One drawback for the current design is a reliance on a water supply.
“The next step in this research is to cut down the water consumption. If the water consumption can be reduced, the suction unit will work for a very long time with little water so that the wall-climbing robot could carry its own water instead of being connected to a supply,” said Li.
The research was published in Physics of Fluids.
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